1. Technical Field of the Invention
The present invention relates to caisson pipe. More particularly, the present invention relates to the removal of caisson pipe of single-leg caisson decks and the removal of the pilings of multi-leg platform jackets by the use of high pressure water.
2. General Background of the Invention
In the drilling and production of oil and gas in deep water conditions, the drilling and production platforms are maintained above the waterline by being supported by a plurality of legs of caissons which have been driven into the bottom of the water. However, once these platforms have been abandoned, it is required that the platform and the supporting legs or caissons be removed.
At present, caisson piles are removed by removing the earth around the outside of the pipe to an acceptable depth below the mud line and then a cutter of some sort is used to cut the caisson. The caisson is then cut below the mud line and the caisson pie is left in the earth. Another method involves a high pressure water blaster or a mechanical cutter of some kind being inserted into the inside of the caisson and lowered to some depth below the mud line. The caisson is then cut. Once again, the remaining pipe is left in the earth below the mud line.
Applicant has reviewed U.S. Pat. No. 6,719,496, a copy of which is submitted herewith the Information Disclosure Statement. The patent addresses the use of ROV installed suction piles. In the patent, the pipes are installed using gravity and suction, and the pipes are removed using water pressure introduced by an ROV. Since the pipes which are being removed by the '496 patent are pipes which are completely submerged, the use of the water surrounding the pipe completes the removal process. There is a need in the industry for a method to remove caisson pipe from a body of water, where the upper end of the pipe is protruding above the surface of the water.
Applicant is submitting herewith an information disclosure statement which includes additional prior art that applicant is aware of at this time.